Full metadata
Title
Synthesis and photophysical characterization of an artificial photosynthetic reaction center exhibiting acid-responsive regulation of charge separation
Description
Non-photochemical quenching (NPQ) is a photoprotective regulatory mechanism essential to the robustness of the photosynthetic apparatus of green plants. Energy flow within the low-light adapted reaction centers is dynamically optimized to match the continuously fluctuating light conditions found in nature. Activated by compartmentalized decreases in pH resulting from photosynthetic activity during periods of elevated photon flux, NPQ induces rapid thermal dissipation of excess excitation energy that would otherwise overwhelm the apparatus’s ability to consume it. Consequently, the frequency of charge separation decreases and the formation of potentially deleterious, high-energy intermediates slows, thereby reducing the threat of photodamage by disallowing their accumulation. Herein is described the synthesis and photophysical analysis of a molecular triad that mimics the effects of NPQ on charge separation within the photosynthetic reaction centers. Steady-state absorption and emission, time-resolved fluorescence, and transient absorption spectroscopies were used to demonstrate reversible quenching of the first singlet excited state affecting the quantum yield of charge separation by approximately one order of magnitude. As in the natural system, the populations of unquenched and quenched states and, therefore, the overall yields of charge separation were found to be dependent upon acid concentration.
Date Created
2015
Contributors
- Pahk, Ian (Author)
- Gust, Devens (Thesis advisor)
- Gould, Ian (Committee member)
- Mujica, Vladimiro (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
viii, 94 pages : illustrations (some color)
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.29909
Statement of Responsibility
by Ian Pahk
Description Source
Retrieved on Aug. 5, 2015
Level of coding
full
Note
thesis
Partial requirement for: Ph.D., Arizona State University, 2015
bibliography
Includes bibliographical references (pages 57-62)
Field of study: Chemistry
System Created
- 2015-06-01 08:12:57
System Modified
- 2021-08-30 01:28:54
- 3 years 2 months ago
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